Moisture is a critical factor in hospital reservoirs of Pseudomonas aeruginosa, such as respiratory equipment, medicines, disinfectants, sinks, mops, food and vegetables. P. aeruginosa, a nosocomial pathogen, is an important cause of infection in immunosuppressed patients, particularly those with neutropenia, burn, cancer, chronic lung disease, diabetes mellitus, immunosuppression, surgery, advanced age; presence of a foreign body, prosthesis, or instrumentation; prolonged hospitalization and antibiotic use. Most common infections include pneumonia, urinary tract infections, skin infections and bacteremia. Resistance of P. aeruginosa in vitro to many antibiotics is widespread and increasing in frequency. For hospital infection control, appropriate sterilization of all equipment, hand washing after patient examination, avoiding unnecessary antibiotics use and contact isolation for multiple resistant P. aeruginosa should be performed.